(1) Field of the Invention
The present invention relates generally to retrieving an unmanned underwater vehicle and, more specifically, to apparatus and method for connecting to and retrieving an unmanned underwater vehicle through a torpedo tube of a submarine.
(2) Description of the Prior Art
Unmanned underwater vehicles (UUVs) may be used for numerous military and non-military purposes including surveillance either stationary or trailing, monitoring various types of sea traffic, monitoring animal and plant life, mapping, weapon systems, and the like, depending on the UUV instrumentation, sensor arrays and the like. In some cases, it will be desirable to retrieve the UUV to obtain stored intelligence, to update equipment, perform maintenance, and program for new missions. Although the UUV may be recovered by ship, it may also be desirable to recover the UUV by means of a submarine whereby the retrieval and recovery may be made entirely underwater.
Relatively complicated apparatus have been used in the past as discussed below to recover vehicles through the torpedo tube of a submarine including multiple pistons, sleeves, electrical connections and the like. It would be desirable to simplify such a procedure. As well, it would be desirable to provide a cable connection to the UUV rather than a male-female connection which may be more difficult to effect. Other patents listed below also provide information about UUVs and interconnection to a trailing cable but not for winching purposes.
U.S. Pat. No. 5,447,115, issued Sep. 5, 1995, to P. E. Moody, which is incorporated herein by reference, discloses an unmanned underwater vehicle recovery device being joinable with the breech of an existing torpedo tube. The recovery device comprises a plurality of concentric tubes which telescope through the torpedo tube to the exterior of the hull of a submarine to provide a mechanism for aligning the recovered unmanned underwater vehicle with the torpedo tube launchway. A recovery vehicle is held within the recovery device by a deployable tether. During recovery, the recovery vehicle is launched from the recovery device in the torpedo tube of the submarine. The recovery vehicle travels out and mates with a coupling at the rear of the unmanned underwater vehicle. The tether is retracted and the joined recovery vehicle/unmanned underwater vehicle is pulled into the torpedo tube launchway. The concentric tubes are retracted and the unmanned underwater vehicle is left in the torpedo tube.
U.S. Pat. No. 5,398,636, issued Mar. 21, 1995, to C. F. Hillenbrand, which is incorporated herein by reference, discloses a submarine that trails a fiber optic cable and an undersea vehicle that is controlled by the cable. A missile/torpedo trails a second cable that is to be coupled to the first cable. The second cable has a segment suspended vertically underwater between a buoyant pod and a sea anchor type buoy. The undersea vehicle, or Autonomous Undersea Vehicle (AUV), hunts for the pod by conventional homing components, and the cable capturing arms on the vehicle direct the cable""s movement relative to the vehicle into a pod mating position that achieves optical coupling of the two cables. In one embodiment, two arms are pivotally mounted to the vehicle""s sides so one arm captures the suspended cable segment directing it into a slot so a male socket in the underside of the pod mates with a female socket in the slot. Another embodiment accomplishes the same result with a device in which the arms are formed at offshoots of a forked cable pickup device in the noise of the AUV. However, in the area of the mechanism which affects the final bringing of the AUV into a directly coupled and mated position with the pod, the patentee""s descriptions are indefinite, vague, and regarding certain points baffling, even including the possibility of extraction of information from his graphics. Providing the mechanical solutions for bringing a pod hunting UUV into a connected relationship with the pod via a cable trailing therefrom is difficult. The efforts of the patentee further involved a requirement to optically couple two fiber optic link terminals at the pod UUV interface, which further complicates the solution. The present invention overcomes these problems and is a solution in which the complication of coupling the fiber links is eliminated.
U.S. Pat. No. 5,396,859, issued Mar. 14, 1995, to Hillenbrand et al., which is incorporated herein by reference, discloses another embodiment of the device described above in U.S. Pat. No. 5,398,636.
U.S. Pat. No. 5,291,194, issued Mar. 1, 1994, to G. H. Ames, which is incorporated herein by reference, discloses an apparatus for interconnecting an unmanned underwater vehicle (UUV) and a free-floating pod. The apparatus comprises a communications cable extending between the pod and a less buoyant buoy, the buoy being in communication with a distal station, a mobile UUV in communication with a control vessel, connector structure on the UUV adapted to intercept the cable and adapted to slide along the cable toward the pod, and complementary engagement structure on the UUV and the pod adapted to cause the UUV to engage the pod in a preselected orientation and azimuth, to place the control vessel in communication with the distal station.
U.S. Pat. No. 3,757,722, issued Sep. 11, 1973, to R. L. Seiple, discloses a docking system that employs a haul down winch to recover and secure a swimmer delivery vehicle to the deck of a large submarine. A buoyancy system is used to deploy a haul down line in a vertical position extending above the submarine vehicle. An acoustic pulse transmitter provides guidance signals to direct the small swimmer delivery submersible to a point of engagement with the haul down line. An attachment means is secured to the line and cooperates with a capture socket carried on the nose of the submersible vehicle. A line capture and guidance device is also mounted on the nose of the submersible swimmer delivery vehicle to assist in attaching the vehicle to the haul down line.
In summary, while the prior art shows various systems relating to UUVs, the prior art does not provide a simplified system for attaching a cable to a UUV for winching the UUV aboard through a UUV receive tube, such as a torpedo tube of a submarine. Consequently, there remains a need for a system that may be used to connect with a trailing cable of a UUV for winching of the UUV into the torpedo tube. As an option, it would be desirable that the system provide for full use of the torpedo tube with virtually no modifications to the torpedo tube. Those skilled in the art will appreciate the present invention that addresses the above and other problems.
Accordingly, it is an object of the present invention to provide an improved method and apparatus for retrieving a UUV.
It is yet another object of the present invention to provide a means for attaching to a trailing cable of a UUV for hauling the UUV aboard a submarine.
These and other objects, features, and advantages of the present invention will become apparent from the drawings, the descriptions given herein, and the appended claims.
In accordance with the present invention, a method is provided for retrieving an untethered submarine tube-retrievable unmanned underwater vehicle (UUV). The untethered submarine tube-retrievable UUV has a capture cable extending therefrom. The capture cable has attached thereto, intermediate the first UUV and the capture cable""s trailing end, a sender transducer unit for producing a homing beacon signal. The sender transducer unit may be housed in a pod which additionally serves the purpose of being a first mechanical jam. The capture cable further has attached at its trailing end an element for exerting a cable extending force on the capture cable. This element may serve as a second mechanical jam. The method may comprise one or more steps such as, for instance, attaching a winching cable to a tethered homing signal seeking unmanned underwater vehicle (UUV), launching the tethered homing signal seeking UUV from a UUV retrieve tube of a submarine. A winching cable towed by the tethered homing signal seeking UUV is guided to and physically secured, but not necessarily electrically or optically connected, to the capture cable. Other steps may comprise providing one or more capture arms that extend laterally from the tethered homing signal seeking UUV to form one or more respective apexes between the capture arms and a body of the tethered homing signal seeking UUV. In a preferred embodiment, a cable snagging eye-member is provided at each of the one or more apex. Each cable snagging eye-member has formed therein an eye-opening preferably of sufficient cross-sectional size to allow the cable snagging eye-member to freely slide along the capture cable when the capture cable is snagged therein. Other steps may comprise impinging a capture arm against the capture cable to guide the capture cable to a respective apex and into a snagged condition within the eye-opening of the cable snagging eye-member. The untethered submarine tube-retrievable UUV is retrieved by pulling the winching cable to slide the cable snagging eye-member along the capture cable until the capture cable engages the first mechanical jam or the second mechanical jam. Continued pulling hauls the untethered submarine tube-retrievable UUV into the UUV retrieve tube of the submarine.
In a preferred embodiment, the sender transducer unit and the force exerting element at the trailing end of the capture cable singly and collectively present substantially less inertial and drag resistance to a force to move them through water than an inertial and drag resistance which the untethered submarine tube-retrievable UUV presents, whereby the cable snagging eye-member will always slide along the capture cable toward the first mechanical jam or the second mechanical jam.
Other method steps may comprise providing a split in the winching cable with first and second ends, attaching the first end to a first cable snagging eye-member, and attaching the second end to a second cable snagging eye-member. In one preferred embodiment, the first and second cable snagging eye-members are detachable from the tethered homing signal seeking UUV.
The invention also provides a system for retrieving an untethered submarine tube-retrievable UUV, which may comprise one or more elements such as the submarine UUV retrieve tube, a capture cable trailing from the untethered submarine tube-retrievable UUV carrying a homing signal beacon, a tethered homing signal seeking UUV carrying a receiver transducer for receiving the homing beacon signal to guide the tethered homing signal seeking UUV toward the homing beacon signal and the capture cable, and a winching cable secured to the tethered homing signal seeking UUV and extendable through the UUV retrieve tube. A plurality of extendable capture arms are mounted to the tethered homing signal seeking UUV for engaging the capture cable, and a plurality of cable snagging eye-members mounted at respective apexes of the capture arms.
In one preferred embodiment, the plurality of cable snagging eye-members are respectively detachably mounted to a body of the tethered homing signal seeking UUV by means of sunderable fastening arrangements for retaining the plurality of cable snagging eye-members fastened to the body. The winching cable may be secured to the second tethered homing signal seeking UUV by a split cable arrangement connecting to a corresponding plurality of attachment points on the respective cable snagging eye-members, whereby a collective sundering of the plurality of fastening arrangements separates the plurality of cable snagging eye-members from the body of the tethered homing signal seeking UUV.